Nuclear physicist Edward Teller says that the jury is still out on whether or not greenhouse gases are leading to global warming, but that contemporary technology offers considerably cheaper options for addressing any global warming effects than politicians and environmentalists are considering.

* One approach, first proposed by theorist Freeman Dyson in 1979, would counteract any warming effect of greenhouse gases by diminishing by about 1 percent the amount of sunlight reaching the Earth's surface.

* This could be done by deliberately introducing fine particles -- such as those thrown up naturally from volcanoes -- into the upper atmosphere to scatter sunlight and heat back into space.

* Such a solution might cost as much as $1 billion a year -- or just $100 million if technologically advanced options were employed.

* That would be between 0.1 percent and 1 percent of the $100 billion a year it is estimated would be required to price-ration fossil fuel usage down to 1990 levels in the United States alone.

Sorry I don't speak Finnish. I followed the debate here from Tim Lambert's Deltoid blog, and wanted to respond to a comment re geoengineering.

We should remember Edward Teller endorsed Reagan's 'Star Wars' when no reputable scientist at the time thought that it could be made to work (and it was eventually stealthily abandoned).

The below post from Realclimate has some good thoughts about geoengineering.

http://peakoildebunked.blogspot.com/2006/01/217-geoengineering.html

Nuclear physicist Edward Teller says that the jury is still out on whether or not greenhouse gases are leading to global warming, but that contemporary technology offers considerably cheaper options for addressing any global warming effects than politicians and environmentalists are considering.

There was an interesting article in the NY Times this week on possible geo-engineering solutions to the global warming problem. The story revolves around a paper that Paul Crutzen (Nobel Prize winner for chemistry related to the CFC/ozone depletion link) has written about deliberately adding sulphate aerosols in the stratosphere to increase the albedo and cool the planet - analogous to the natural effects of volcanoes. The paper is being published in Climatic Change, but unusually, with a suite of commentary articles by other scientists. This is because geo-engineering solutions do not have a good pedigree and, regardless of their merit or true potential, are often seized upon by people who for various reasons do not want to reduce greenhouse gas emissions. However, these ideas keep popping up naturally since significant emission cuts continue to be seen as difficult to acheive, and so should be considered fairly. After all, if there was a cheaper way to deal with the CO2 problem, or even a way to buy time, shouldn't we take it?

First a little history [Update: See Spencer Weart's essay on the history of climate modification ideas]. Geo-engineering ideas first reached the public in the 60s when there was still a lot of enthusiasm for technical fixes of the world's problems. One example was suggested by the Soviets who wanted to melt the Arctic (either using soot or nuclear devices) in order to warm up their frozen North. More recently, there was a proposal to dam the Straits of Gibralter in order to prevent more saline Mediterrean Sea water (because of the Aswan Dam) from affecting the North Atlantic conveyor circulation (no, it didn't make sense to us either). With such a pedigree, geo-engineering is generally seen as fringe entertainment at best, although some of the new ideas concerning atmospheric carbon dioxide sequestration are being looked into seriously.

Edward Teller is the scientist most associated publicly with the idea of creating a stratospheric shield to prevent excessive global warming, though he built on an idea from Freeman Dyson (who has subsequently become a bit of global warming contrarian)*. However, as Teller's collaborator Stanislaw Ulam once said after discussing some new ideas with him: "Edward is full of enthusiasm about these possibilities; this is perhaps an indication they will not work". And given Teller's estrangement from the scientific community in his later years, it was not likely that the concept would be taken very seriously, and indeed it hasn't been.

*Which in turn built on a idea from Budyko...(see comment below).

But now Paul Crutzen has stepped into the fray. He has a much more solid reputation amongst climate scientists than Teller, and thus his ideas will be taken more seriously. I haven't seen the new paper yet (it's out in August) but there are a number of questions that need to be addressed before any geo-engineering proposal combatting global warming should be thought of as anything more than an interesting idea. First, the idea has to actually work, second, the side effects need to be minimal, and third, it has to be able to keep up with an increasing forcing from ever higher greenhouse gas levels, and fourth, it has to be cheaper than the simply reducing emissions at source. These are formidable hurdles.

Would it work? In most of the cases under discussion the target is the global mean temperature, and so something that balances the global radiative forcing of greenhouse gas increases is likely to 'work'. However, having no global mean forcing is not the same as having no climate change. A world with higher GHGs and more stratospheric aerosols is not the same as a world with neither.

Thus there will be side effects. For the stratospheric sulphate idea, these fall into two classes - changes to the physical climate as a function of the changes in heating profiles in solar and longwave radiation, and chemical and ecological effects from the addition of so much sulphur to the system. Physically, one could expect a slight decrease in surface evaporation (a 'dimming' effect) and related changes to precipitation, a warming of the tropopause and lower stratosphere (and changes in static stability), increased Eurasian 'winter warming' effects (related to shifts in the wind patterns as are seen in the aftermath ofvolcanoes). Chemically, there will be an increase in ozone depletion (due to increases in heterogenous surface chemistry in the stratosphere), increases in acid rain, possibly an increase in high cirrus cloud cover due to indirect effects of the sulphates on cloud lifetime. Light characteristics (the ratio of diffuse to direct sunlight) will change, and the biosphere may react to that. Dealing with the legal liability for these predictable consequences would promise to be a lively area of class action litigation.... On the positive side, sunsets will probably be more colorful.

Could it keep up? GHGs (particularly CO2) are accumulating in the atmosphere and so even with constant present-day emissions, the problem will continue to get worse. Any sulphates put in the stratosphere will only last a couple of years or so and need to be constantly updated to maintain concentrations. Therefore the need for the stratospheric sulphates will continue to increase much faster than any growth of CO2 emissions. This ever-increasing demand, coupled with the impossibility of stopping once this path is embarked upon is possibly the biggest concern.

How expensive would it be? I will leave the detailed costing to others, but stemming from the last point, the cost will continue to rise indefinitely into the future unless this proposal is coupled with an concommittant effort to reduce CO2 emissions (and concentrations) such that the need for the sulphates will diminish in time.

Crutzen's paper may well address these issues comprehensively (and I look forward to seeing it) but, in my opinion, the proposals are unlikely to gain much traction. Maybe an analogy is useful to see why. Think of the climate as a small boat on a rather choppy ocean. Under normal circumstances the boat will rock to and fro, and there is a finite risk that the boat could be overturned by a rogue wave. But now one of the passengers has decided to stand up and is deliberately rocking the boat ever more violently. Someone suggests that this is likely to increase the chances of the boat capsizing. Another passenger then proposes that with his knowledge of chaotic dynamics he can counterbalance the first passenger and indeed, counter the natural rocking caused by the waves. But to do so he needs a huge array of sensors and enormous computational reasources to be ready to react efficiently but still wouldn't be able to guarantee absolute stability, and indeed, since the system is untested it might make things worse.

So is the answer to a known and increasing human influence on climate an ever more elaborate system to control the climate? Or should the person rocking the boat just sit down?

Thank you for the comment - I created a new post based on your comment saying basically following:

I am not able to comment on the feasibility of the proposed geoengineering mechanism technically, but due to the huge relevance of the global warming problem and the difficulty in introducing big reduction in the emission of the gases, every proposal should be considered.

I speculated then who would take care of the geoengineering. Who would pay the costs and who would make decisions on the optimal temperature.

If humanity must be able to control the atmosphere through genengineering, then we really need the enigineer doing the engineering and the politicians to make the decisions. It would be a huge public good effort, if the geoengineering would be managed internationally e.g through UN or G7.

But the same is even more true for the case if we have to solve the problem through reductions of gas emissions. We have a huge problem ("tragedy of commons") which must be managed internationally. Or thorugh US forcing the other countries to follow certain rules. (For that US seems to be too weak and at least today it looks like US has not commitment to solve the problem ??)

I don't think we know, but I imagine it would be an international programme, like AIDS or malaria.

A better (or more hopeful) example might be NATO during the Cold War, when nations genuinely committed to particular numbers of divisions and weapons systems (but cheated on occasion).

Or even the CFC Treaty (Montreal Protocol) where the Europeans at first resisted, but finally agreed to American led cuts in CFCs, and by Treaty the Emerging Markets (Third World) are now forced to follow suit (with threat of trade sanctions).

2. on CO2 emissions the same problems of what economists call 'game theory' arise.

in fact the UK's new climate change bill (20% reductions by 2020, 60% by 2050) explicitly recognises the need for 'credible commitment' ie by committing ourselves to the process, we make it more likely that other countries will follow. This is something derived from game theory.

I think the US can lead on this, and needs to, but I do not think it can compel. It's only real 'weapon' would be the threat of trade sanctions, but that would have many other negative impacts.

However I do believe that if the US and the EU lead on this, then other nations will follow suit.

The US + EU + Japan/Korea/Taiwan/Singapore is over 60% of world emissions, currently, and something like 80% of world historic CO2 emissions. China and India will be very important, so is rainforest deforestation, but again if we move first, we show the way.

It may take some time for China and India to see the reality, but they are probably worse affected by global warming than we are, so it is in their interests that actions are taken.

In Canada they are now losing millions of hectares of coniferous forest to bud worms, which formerly the cold winters killed off before they could infest the trees. I hope that Finland escapes this devastating problem.

"in fact the UK's new climate change bill (20% reductions by 2020, 60% by 2050) explicitly recognises the need for 'credible commitment' ie by committing ourselves to the process, we make it more likely that other countries will follow. This is something derived from game theory."

I wonder which game theory result you refer to.

I can imagine the "others will follow"-model will work in small communities (neighbourhoods, churches) with high or medium level of group cohesion and maybe even Netherlands could follow Britain but what about China.

I understand that chinese people are rather negative towards Britain based on history like the Opium War. Also the culture and norms are very different to the british one's ?

Samuel Bowles e.g. says that heterogenous communities are less efficient on solving problems like this Tragedy of Commons (=climate warming). The most heterogenous human community is the whole human kind.